Hi; just wanted to report back:mspider65 wrote: ↑Nov 20 2021 2:17amYes a reistor voltage divider works well, but in the other direction, a 5v buffer/driver is useful not only for safety reason but also to have a better connection reliability.
The cable that goes to the display is quite long an the noise margin using a 3.3v driver and a 5v receiver is small and, even though the cable going to the controller is short, it is still in a noisy environment with quite high currents switching at PWM frequency.
I got it to work! Great, great project @mspider65!
As stated, I build it off available parts. (A bare ESP32Wroom, a tiny DC-DC Step Down Module 6-55V to 5V plus AMS1117 3.3V regulator, stacked ontop of each other.) But you and @Beli were correct in that my intended level shifter circiut (TXB0108) did NOT work! (The communication to the motor-controller did work, but not towards the display - lots of CRC errors in debug seen.
So I tried for the Rx side direct connection and the Tx side a Ohm voltage divider (both for controller & LCD). That works so far. I still need to see, if it works reliably. I cross my fingers it does, as my setup is outside of the controller / motor case.
I am happy how I got the individual parts squeezed together into a small enclosure, which will hide somewhere ontop of the motor. (Although direct soldering of the bare ESP module is tricky...)
Thanks again for sharing this, @mspider. Especially, the hall optimization, the great App and the entire concept of the 'man-in-the-middle approach'!